Observation of intrinsic emission in β-BiNbO4 available for excitation of both UV light and high energy irradiation

Abstract

β-BiNbO₄ with a high temperature triclinic form was prepared via a high-temperature solid-state reaction ceramic method. Structural refinement and surface characteristic studies were performed. The optical absorption, and electronic calculation of the band structures and density of states were also studied. β-BiNbO₄ ceramic has an indirect transition with a band energy of 3.05 eV. The valence band is dominated by O-2p states whereas the conduction band has predominantly Nb 4d and Bi 6s character. The intrinsic luminescence properties of β-BiNbO₄ were reported, and present a blue emission band peak at 435 nm under the excitation of UV light. The β-BiNbO₄ ceramic presents scintillation properties under high energy irradiation. The luminescence was studied via the combinations of the color centers, band calculation and energy transfer from NbO₆ to Bi³⁺ in the lattices. The thermal quenching and activation energy for the luminescence were reported. β-BiNbO₄ has potential applications in photoluminescence and scintillation materials.